A Rusalka is the restless and often deadly spirit of a drowned girl that has come back near the body of water where she died. When people are near, particularly young men, the Rusalki will attempt to lure them close enough to kill them.
As spirits, the Rusalki have an ethereal presence and appear semi-transparent. Usually they take the form of a young girl, with tendrils of seaweed dangling from their arms.
Their sprites are similar to those of Shades, but blue instead of gray. When faced before battle, they appear ashen-faced and have staring, lifeless eyes.
The quiescent sea-god Eortis has some interest in rusalki, since they are associated with water and are therefore under his purview. They may also be of concern to Killian, who took over Eortis's duties since the latter vanished in the Chaos Wars.
Beyla refers to them as "sisters of Eliaem" and cautions that many are wily and difficult to locate, finding ways to conceal their presence for fear of being sent to the halls of Lims-Kragma. Finding them, therefore, requires cleverness. Owyn Beleforte, facing them in battle, regrets not having studied more about Lims-Kragma and temple magic.
An artifact, Eliaem's Heart, is said to grant the power to summon a rusalki lover.
Rusalki have a long range of motion and powerful attacks, and can hit targets with bursts of magical energy even at close range; those who fight them must take care to be shielded from harm or to frequently replenish health. However, rusalki can be injured with most weapons and spells. The spell River Song is especially designed to affect them.
Like Shades, Rusalki sink into the ground and out of sight when defeated. This ends battles on an uncertain note, since the party never feels sure that the vanished spirits will not return.
When the party first visits Silden, they must travel to the Temple of Eortis and petition Beyla, the high priestess of Eortis, for a chance to perform a duty of obeisance in exchange for healing. Beyla tells them of complaints that the rusalki lingering near local rivers "have become disturbed"; laying them all to rest might win Eortis's favor. Eortis confirms this by healing them as they leave to begin the quest.
After defeating the fifteen rusalki lurking on the banks between Silden and Sloop, the party can return to Beyla in any time of sickness or injury and be completely healed.
While traveling through the Green Heart, the party may encounter a mysteriously non-hostile rusalki who asks them to retrieve Eliaem's Heart from a moredhel spellcaster who is using it to control other rusalki. To do so, they must defeat both the spellcaster and the four rusalki he controls. If the party returns to the mysterious rusalki, makes sure to have 13 inventory spaces free, and returns the Heart to her, she thanks them on behalf of herself and her kin, giving them travel advice, Rations, and a mysterious shell -- which, she says, has value they might never be able to imagine.
An old woman in Darkmoor had lost her family to the rusalki. She chants this about them: "Innocence lost. Lost. Spring blossoms robbed of carnal bliss, the Goddess of Death their first kiss. Their first kiss. They will shrink away from her touch, they hate her so. Hate her so. Find the Magic Touch or you too may feel her icy kiss."
- In Slavic folklore, a  (pl. 'rusalki') is typically a feminine spirit associated with a body of water. Elements of danger, tragedy, and uncleanliness were added in modern versions, which usually present rusalki as the unquiet ghosts of young women bound to the waterways in which they met untimely deaths, doomed to drown others in turn until their lives are avenged or their spirits cleansed.